Various immune mechanisms appear to be important in the body's defenses against the hepatitis B virus. Much is known about the humoral antibodies, anti-HBs and anti-HBc. Relatively little conclusive research has been done, however, in investigating the cellular immune response to this disease, even though this immune mechanism may be of prime importance in the clearing of virus and in determining whether the patient will become a chronic carrier of the disease. The goal of this study is to determine whether a simplified technique for assessing cellular immunity, leukocyte migration in an agarose plate, is a valid procedure for identifying those people with this type of immunity. If the technique is demonstrated to be valid, the then characteristics of the cellular immune response to hepatitis B can be fully defined. Initial studies investigating validity of the procedure are currently in progress.